The present invention relates to a steering lock apparatus for use in vehicles and the like.
Conventionally, a cylinder lock that allows locking and unlocking without a key has been disclosed in e.g., Japanese Utility Model Kokoku Publication No. 61-28851. This cylinder lock has a rotor equipped with tumblers, and a rotational cylinder with a tumbler engagement groove formed on the inner circumferential face is provided on the outer circumferential face of the rotor. On the outer circumferential face of the rotational cylinder, there is provided a hole for fitting a top end portion of a plunger driven by an electromagnetic solenoid. When the electromagnetic solenoid is off, the plunger is fit into the hole to prevent rotation of the rotational cylinder, whereas when the electromagnetic solenoid is on, the plunger comes out of the hole to bring the rotational cylinder into a rotatable state. For unlocking the cylinder lock with use of a key, the key is inserted into the rotor so that the tumblers sink into the rotor, which releases engagement between the tumblers and the rotational cylinder and thereby enables the rotor to rotate in precisely the same way as general cylinder locks. For unlocking the cylinder lock without use of a key, the electromagnetic solenoid is operated to pull the plunger out of the hole of the rotational cylinder so as to make the rotational cylinder rotatable. Consequently, holding and rotating a knob provided on the front face of the rotor implements cooperative rotation of the rotor and the rotational cylinder since the tumblers of the rotor are in engagement with the tumbler engagement groove of the rotational cylinder.
However in the above-mentioned known steering lock apparatus, if the rotational cylinder is under rotating operation when the electromagnetic solenoid is turned on and the top end portion of the plunger is about to escape from the hole, the top end portion of the plunger comes into contact with the lateral wall of the hole and is caught thereon, which may cause a disadvantage that the rotational cylinder is not unlocked even if the electromagnetic solenoid is turned on.
In order to solve the above problem, a steering lock apparatus of the present invention is composed of: a rotational member having an engagement recess portion; an operating portion positioned in a front side of the rotational member and connected to the rotational member; a holder for holding the rotational member movably in forward and backward directions and for holding the same rotatably in a rear position; an actuator driven by a signal transmitted by a controller upon detection of the rotational member being operated to a rear side; and a lock member that is operated by the actuator and inserted into the engagement recess portion of the rotational member for preventing rotation of the rotational member, wherein an engagement release position where the engagement of the engagement recess portion of the rotational member and the lock member is released is provided between a front position and a rear position, and a prevention means for preventing rotation of the rotational member is provided so as to prevent engagement of the lock member and a lateral wall of the engagement recess portion of the rotational member in the engagement release position.
In such a structure, when the lock member gets out of the engagement recess portion of the rotational member to unlock the rotational member, rotation of the rotational member is prevented by the prevention means if rotational force is added to the rotational member, which prevents engagement between the lateral wall of the engagement recess portion of the rotational member and the lock member, thereby ensuring execution of unlocking operation.